Rotary pump for handling viscous materials



June 18, 1957 F. P. NEBEL 2,795,030

ROTARY PUMP FOR HANDLING VISCOUS MATERIALS Filed May 24, 1954- 5Shee'ts-Sheet 1 INVENTOP F. P. NEBEL ROTARY PUMP FOR HANDLING VISCOUS'MATERIALS June 18, 1957 5 Sheets-Sheet 2 Filed May 24, l954 M Q, 7 V 1 mA d n M W W/ W wrewra/P June 18, 1957 F. P. NEBEL ROTARY PUMP FORHANDLING VISCOUS MATERIALS 5 Sheets-Sheet 3 Filed May 24. 1954 R m M m wF/ V a W yi7/ii F. P. NEBEL 2,796,030

ROTARY PUMP FOR HANDLING vIscous MATERIALS June 18, 1957 5 Sheets-Sheet4 Filed May 24. 1954*- INVENTOP 4M June 18, 1957 F. P. NEBEL 2,796,030

ROTARY PUMP FOR HANDLING VISCOUS MATERIALS Filed May 24. 1954* 5Sheets-Sheet 5 A WW United State Patmt ROTARY PUMP FOR HANDLING VISCOUSMATERIALS Franz Philip Nebel, Nurnberg, Germany Application May 24,1954, Serial No. 431,951

Claims priority, application Germany May 29, 1953 20 Claims. (Cl.103-124) The invention relates to a rotary pump for handling viscousmaterials, wherein a positively controlled oscillating abutment followsthe outline of the impeller.

Rotary pumps of a Wide variety of types are known. All previously knownrotary pumps are affected with a serious disadvantage, that of unduevibration. This is not very troublesome at low speeds of the impeller insuch pumps. However, such pumps will not tolerate very high impellerspeeds without damage to themselves and excessive percussion of thesurroundings. At the same time, in order for the efliciency of suchpumps to be high, a fairly high rotational speed is often required.There have been considerable efforts to achieve smooth operation at highrotational speeds. Heretofore, however, these attempts have failedbecause it was believed that the difiiculties in question could beovercome by simply improving the control of the oscillating member;whereas this was without effect on the smoothness of operation of thepump. The underlying cause of the trouble has not previously beenrecognized. The defect that has actually prevented the achievement ofhigh impeller speeds in known pumps consists in the shape of theoscillating member; in the transverse wearplate, provided with a sharpor rounded edge and connected with the oscillating member; and in theplacement and movement of the oscillating member relative to theimpeller, as well as the shape of the latter.

The present invention is addressed to the problem of providing a rotarypump in which these defectsare eliminated.

This problem is solved substantially in thatthe oscillating member ispivoted and provided with a non-rotating cylindrical contact elementwiping the surface of the impeller, the center of which elementdescribes a circular arc, whereas its positions relative to therevolving impeller trace at Well-rounded curve determining a still morerounded track for the cams actuated in conjunction with the oscillatingabutment. Another feature of the inventionconsists in that the tangentto the circle described by the impeller and the secant surface of theimpeller formv an angle such that the wear part of the oscillatingabutment will pass only away from the tip of the impeller along thesurface in line with the apex, as the impeller revolves. A. furtherfeature consists in that the surface and the tangent form an angle ofsuch magnitude that the accelerations and decelerations of the inertiaforces acting on the control of the oscillating. member, due to theoscillating movements of the latter and dependent an. the speed of thepump, are kept within allowablelimits; that is, the magnitude of theangle depends on.v the rotational speed, and mustnot exceed 100. Stillanother feature consists in that the radius R of the oscillatingabutment is intermediate between R1+R1/3 and R1/ 2, where R1 is thedistance from the center of the impeller shaft to the center of thepivot of the abutment.

A preferred embodiment of the control mechanism is characterized in thattwo adjacent parallel rollers mounted on the same or on separate leverarms positively control the oscillating abutment, one roller followingthe outside track and the other the inside track of the same or ofseparate cams. Another feature consists in that the roller lever,rigidly connected with the oscillating abutment by a shaft, beingmounted e. g. on the shaft of the abutment itself, preferably by meansof a forked member fixed on the shaft and two set-screws, is fixable anddisplaceable in either direction in order to permit adjustment of thedesired clearance between impeller and abutment.

A preferred attachment of the cams is characterized in that the cams arefixably mounted, preferably on the cam and/ or impeller shaft, andadjustable e. g. by means of stationary forked members and set-screws. Apreferred means of damping the inertia forces of the oscillatingabutment is characterized in that counterweights are provided to balancethe inertia forces of the abutment, e. g. by providing the abutmentshaft with a crank to drive a flywheel with counterweight by means of aconnecting rod. A variant consists in that a counterweight is providedon an auxiliary shaft bearing the cams. A further feature of theinvention consists in that the impeller bears two rotating side platesintegral therewith. Another feature consists in that the cover of thepump housing is held down on the housing by a closure means, for examplea bridge with a pressure screw, for ready removability, and sealed witha gasket. A further feature consists in that the liner in the interiorof the pump is attached by means of pins for ease of replacement. In apreferred embodiment of the pump housing, the latter is provided with anopening on the suction side, closed off with a readily removable cover,e. g. held in place only by a lever and counterweight. Finally, anadditional feature consists in that the pump system and the cam or drivesystem each constitute a separate subassembly but are mounted on acommon baseplate, so that the pump alone can be replaced withoutinterfering with the cam or drive system.

In a pump according to the present invention, the oscillating abutmentis made to follow a well-rounded curve adapted to the outline of theimpeller. The pump is of extremely simple construction, and can beopened quickly for convenient access in a small number of operations.The liner in the housing for contact with the impeller can be readilyand rapidly replaced with the aid of its pin mounting. Thecounterweights provided in the mechanism of the oscillating abutmentcompensate the inertia forces, so that the pump according to the presentinvention is free from excessive vibration. The side plates revolvingwith the impeller keep the abutment from working into the side packing.

Some embodiments of the invention are illustrated, by way of example andnot of limitation, in the accompanying drawing, wherein:

Fig. 1 shows a front view of a rotary pump according to the invention,in median longitudinal section;

Fig. I shows a side view ofthe same, likewise in section;-

Fig. 3 shows the control system, with the pump housing in section;

Fig. 4 shows a diagram of the control system;

Fig. 5 shows another embodiment of the control system, as viewed at V inFig. 6;

Fig. 6 shows the same embodiment in side view and partial section;

Fig. 7 shows a detail VII of Fig. 6;

Fig. 8 shows a detail VIII of Fig. 9;

Fig. 9 shows a view of TX in Fig. 6;

Figs. 10 and 11 schematically show additional embodiments of the controlsystem.

In a pump housing 1, an impeller 3 is rotatably mounted and driven by ashaft 2. The surface of the impeller 3 is wiped by an oscillatingabutment 4, maintaining a seal in known manner between the suction andpressure sides. The abutment 4 is fitted with a nonrotating cylindricalwear member 5 attached by means of screws 6. The housing 1 is fittedwith a readily removable liner 7 attached by means of pins 8. The angle11 formed by the tangent 9 and the surface 10 is such that the wearmember 5 will move relative to the surface 10 in the direction of thearrow x only, namely away from the tip 13. The radius R of theoscillating abutment 4 is intermediate between the values The impeller 3has revolving side plates 14 integrally attached to it. The housing 1has a cover 15 which, being held against the housing 1 by means of ascrew 17 in a bridge 16 attached to the housing, seals the housing 1with the aid of a packing insert 18.

An opening provided on the suction side of the housing 1 is closed offwith a cover 19 held tight against the opening with the aid of a lever22 hearing a counterweight 21.

The oscillating abutment 4 (see Fig. 3) is controlled by means of earns23, 24 fixed on the impeller shaft 2 and acting upon followers 26, 27mounted forkwise on the abutment shaft 25. As Fig. 4 shows, one of thefollowers 26, 27 is always in contact with the corresponding cam 23, 24.The dot and dash line surrounding the impeller 3 in Fig. 1 shows theresulting well-rounded path of the center of the wear part 5 relative tothe surface of the revolving impeller, drawn uniformly equidistant fromthe latter. In Figs. 5-9, there are two parallel cam rollers 28, 29, theroller 28 following the inner track of a cam 31 and roller 29 the outertrack of a cam 32. The rollers 28, 29 are fixably mounted on a shaft 25,and adjustably attached to a fork 34 by means of set-screws 33. The cams31, 32 are likewise fixably mounted on the shaft 2, and attached withset-screws 35 to forks 36 so that the cams 31, 32 can be aligned withthe rollers 28, 29, and vice versa. Fig. 10 shows the arrangement of alever arm 37 on the oscillating abutment 4, which lever arm is connectedby a connecting rod 38 to a flywheel with counterweight 39, serving tobalance the inertia forces of the oscillating abutment 4. In Fig. 11,the inertia forces of the oscillating abutment 4 are balanced by meansof a counterweight 43 provided on an auxiliary shaft 42 hearing the cams41.

What I claim is:

l. A rotary pump for handling viscous materials, comprising an impeller,a shaft for mounting said impeller, a positively controlled oscillatingabutment wiping the surface of said impeller, a pivot for mounting saidabutment, a non-rotating cylindrical wear member. removably attached tosaid abutment, and a plurality of controlling cams driven in conjunctionwith said abutment,

and

said abutment having a radius R lying between a in 2 and R1 3 wherein R1stands for the distance from the center of said impeller-shaft to thecenter of the pivot of said abutment, the radius of said wear member andthe radius R1 being at the minimum ratio of about 1:17, wherein atangent, drawn to the circle described by the impeller during rotation,and a secant surface of said impeller form an angle which is maximallyand is so adjusted, depending on the rotational speed of the pump andthe viscosity of the material handled, that the wear member on theoscillating abutment will pass in the direction away from the apex ofsaid angle along the surface line of the impeller following therevolving impeller, said cams being fixed on the impeller shaft andacting upon followers mounted on the abutment shaft and provided withcounterweights.

2. A rotary pump according to claim 1, wherein the control cams areco-acting with two control rollers which follow the contour of saidcontrol cams.

3. A rotary pump according to claim 2, wherein the control rollers aremounted on a common control lever arm.

4. A rotary pump according to claim 2, wherein the control rollers aremounted each on a separate control lever arm.

5. A rotary pump according to claim 2, wherein each control lever isassociated with one control cam.

6. A rotary pump according to claim 2, wherein one of the control camhas an inside track and the other of the control cams has an outsidetrack for said control rollers.

7. A rotary pump according to claim 2, wherein both control cams haveoutside tracks for the control rollers.

8. A rotary pump according to claim 2, wherein both control rollers areassociated with a common control cam.

9. A rotary pump according to claim 4, wherein said control levers arefixedly mounted on a shaft rigidly connected to the abutment shaft.

10. A rotary pump according to claim 4, wherein said control levers aresecured on the abutment shaft.

11. A rotary pump according to claim 10, wherein the roller-supportinglevers are mounted on the abutment shaft by means of a forked memberadjustable with set screws in two directions.

12. A rotary pump according to claim 2, wherein the controlling cams aresecured to the impeller shaft.

13. A rotary pump according to claim 12, wherein forked members areprovided for securing the control cams on the impeller shaft, saidforked members having set screws for making said mounting adjustable.

14. A rotary pump according to claim 1, wherein the abutment shaft isprovided with a lever arm associated with a connecting arm forconnecting a flywheel with counterweight to said shaft, serving tobalance the inertia forces of said oscillating abutment.

15. A rotary pump according to claim 1, wherein an auxiliaryshaft isprovided, a cam mounted thereon, a counterweight on said auxiliaryshaft, and connecting means for driving said cam from said abutmentpivot.

16. A rotary pump according to claim 1, wherein said impeller has twolateral plates secured thereto and rotating therewith.

17. A rotary pump according to claim 1, which includes a pump housing,cover means for closing said housing, and readily removable means forsecuring said cover means in air-tight manner on said housing, saidlastmentioned means comprising a bridge-shaped member, pressure screwsfor fastening the same, and a gasket for interposition between the covermeans and the pump housing.

18. A rotary pump according to claim 1 which includes a pump housing, anexchangeable lining therefor, and pins for fastening the same.

19. A rotary pump according to claim 1, including a pump housing havingan opening on the suction side, a readily removable cover for closingthe same, and a lever with a counterweight for holding the cover inplace.

20. A rotary pump according to claim 1, wherein the 5 pump system andthe cam or drive system each constitutes 1,509,051 McBryde Sept. 16,1924 a separate subassembly mounted on a common base plate 2,363,961Hart Nov. 28, 1944 but capable of individual replacement withoutinterfer- FOREIGN PATENTS ence with the other system.

25,849 France Feb. 20, 1923 References Cited in the file of this patent5 i getheflands 1 9 rance ug.

UNITED STATES PATENTS 170,171 Austria Jan. 25, 1952 297,478 Warfh 22,1884 270,335 Switzerland Nov. 16, 1950 506,533 Nasl Oct 10, 1893 641,390Great Britain Aug. 9, 1950 9 tt M y 18, 1909 10 708,73 France May 4,1931

